I'm very close to reforming the Timurids in my Transoxiana game.
The revolution is quite challenging if you don't have the support of even one of the other vassals. Until the Shah dies, try to get alliances with and the support (influence) of as many as you can. Afghanistan and Fars, if I recall, have the most troops. I've done several starts to test and with all four that war of independence is pretty easy; with two it's doable, but by yourself you're fighting between 15-20 extra regiments. And my game must be different than yours because, with CoC installed, the Timurids start with around 20-23 regiments and I start with 14-15 (assuming I'm not going over the force limit) ... so they have a lot more men than I do. To be clear, I'm not playing on easy.
So if you go against that group by yourself, it's 15-20 regiments on your side (assuming you go over the force limit) against 35-40+ regiments. Yeah, if you can kill them as they trickle in, you can make it happen, but in my game I still ended up taking out nine loans to cover my losses and finally peaceed out with my independence and a couple of cores.
But if you can get the support of all four other vassals (check their liberty desire to make sure it's over 80%, and improve your relations with Khorsan because the Timurids make them a march, improving their relationship with them), then it's a pretty simple undertaking. You can get your independence without even taking out loans.
I take my cores back and the highest dev provinces I can: Herat, Mayamana, Sarahkis. Iny my current game, I got those, my cores and money with my war of independence,
I allied with Nogai and Chagatai and dumped my alliances with the vassals. Chagatai eventually pulled me into a war with Ming but I stayed close and retook a bunch of their provinces, fought off some of the smaller stacks, etc.The war lasted forever and when it was done (victory) Chagatai owed me 24 favors.
Next, I took an alliance with Mazandaran and took Khorsan. When that war was over, my truce with the Timurids had burned off and I went back and grabbed most of them. What was left disappeared shortly thereafter. Afghanistan was next but they had several allies so I used my favors with Chagatai to get them in the war.
At this point, I only needed one province to reform the Timurids. Ajam attacked Mazandaran and that area became a free-for-all as every country with an interest piled on. I grabbed the last province I needed and a few more (five I think) and waited for Mazandaran to peace out. Sure enough, in a year, they won the war, doubled their size. Now I'm just waiting for some of the unrest to burn off before reforming the Timurids.
Transoxiana starts with a strong trade node within about 20 years I was making 9 ducats a turn (mosque and marketpace built). I forced the Timurids to give me their trade power.
QQ is next, and then I'm heading for India. Delhi is in the middle of a large war so if they lose, I might take them instead.
Bottom line: if you can get past the independence war, without tanking your economy, it gets pretty easy after that.